Installing insulation under car decking
geoffhazel
| Posted in Energy, Heating & Insulation on
How do you install insulation under a car decking floor where the beams are 4 feet apart? Of course, with joists 16″ oc, you can put metal wires or string between or across the joists to hold up the material, but what do you do on these wide bays?
Replies
spray foam
Do like they do in commercial construction ... or something similar. They use long stick pins (not sure what they are called). In e.g. metal building construction, they glue e.g. 12" stick pins to the metal wall panel or on the metal floor deck above. They install vinyl backed insulation and force a friction fit square metal washer onto the pin. May not work w/ a wood structure, but I got a feeling there is a product out there for e.g. post and beam wood construction.
Other options are rigid foam insulation and a system of attachments ... like roof deck screws (which BTW come in lengths up to like 16") and roofing washers.
You have an elevated wood car deck? Somewhat unusual.
Edited 11/22/2009 10:24 am ET by Clewless1
If using fiberglass You buy insulation cut to fit the bays and then support it using your choice of :
1) baling twine
2) wood lathe
3) nylon netting
Twine and netting is installed using a stapler designed for the purpose.
Rigid foam can be tacked up using 16d. toe nails or set on cleats then foamed into place.
Edited 11/22/2009 11:07 am by dovetail97128
I got a feeling that twine and netting might sag a lot right off the bat. Wood lathe over that span would sag over time, I'd think. Key is to ensure a good fit tight up against the deck and I wouldn't be comfortable with any of your options in that regard.
Edited 11/23/2009 8:24 pm ET by Clewless1
You might not be. What I gave was the methods that were the most common methods used around here when car decking 4' o.c. was the standard floor building method around here.
Life is Good
Didn't mean for it to sound critical of you. Just saying the approaches you mentioned may have problems for the reason stated. Your point of view is still very respected.
No sweat.... I don't know of any better methods to use, all those I listed had problems, mostly the sag you mentioned. Careful installation was the key as far as I was concerned when I was doing the install or G.C. the job.
Of all of them the nylon twine laced diagonally and in an "X" pattern across the bays seemed best.
Course there was the time I hit a local mill up for scrap headed to their chipper and got 1x scraps and used a wide crown stapler to install it. That was probably the best install.
Life is Good